Paul Weitz’s idiosyncratic road movie revolves around Elle Reid (Lily Tomlin), a pensive poet and semi-retired academic still grieving for Violet, her partner for 30 years.

Elle’s day begins as she coldly dismisses much-younger Olivia (Judy Greer), with whom she’s had a four-month fling. Then Elle’s 18-year-old granddaughter Sage (Julia Garner) appears on her doorstep, asking for $600 to pay for an abortion that’s already scheduled for later that afternoon.

Having just paid off her bills, Elle’s broke. She cannot use her credit cards since she cut them up and made a wind chime out of the plastic pieces, wryly explaining, “I’m transmogrifying my life into art.”

Since going to Sage’s brusque, judgmental businesswoman mother (Marcia Gay Harden) is out of the question, they climb into Violet’s ’55 Dodge Royal Lancer and begin driving around Los Angeles, trying to scrounge up cash.

First stop is to shake-down the weasel (Nat Wolff) who got Sage pregnant. Then Elle tries to sell her feminist first-editions to a bookstore/cafe owner (Elizabeth Pena) and retrieve a loan from a transgender tattoo artist (Laverne Cox). Most memorable among those they visit is Karl (Sam Elliott), who has never forgiven or forgotten Elle.

Written and directed by Weitz (“About a Boy”), it’s a quirky character study, a comedic drama that’s perfectly tailored for Tomlin’s talents. She obviously understands angry, misanthropic Elle.

“I’ve never really been the star of a movie,” Tomlin says, even though Time magazine featured her on its cover back in 1977, proclaiming her the “new queen of comedy.”

FYI: Tomlin had been offered the Time cover previously — on the condition that she reveal her homosexuality — but she refused, noting, “I was always very active in gay issues and most people knew I was gay, but they didn’t make a big deal out of it.”

And Tomlin is teaming with Jane Fonda for Netflix’s second season of “Grace and Frankie,” in which they play frenemies whose newly outed husbands announce plans to marry.

On the Granger Movie Gauge of 1 to 10, “Grandma” is an acerbic, insightful 7 — and Tomlin’s peppery performance.